Oil pressure supply device

ABSTRACT

An oil pressure supply device includes: a first oil pump configured to be operated by a traveling drive source of a vehicle; a second oil pump configured to be operated by a motor different from the traveling drive source and to be switched between an operation and a stop according to a traveling condition of the vehicle; a pressure regulating circuit configured to regulate an oil pressure generated by the first oil pump and the second oil pump and supply the regulated oil pressure to an oil chamber; an oil passage configured to connect the second oil pump with an oil source; and a check valve provided in the oil passage.

TECHNICAL FIELD

The present invention relates to an oil pressure supply device.

BACKGROUND ART

JP 2016-79992 A discloses an oil pressure supply device that supplies an oil pressure to an automatic transmission or the like. The oil pressure supply device includes two pumps, that is, a mechanical oil pump operated by an engine and an electric oil pump operated by a motor. The oil pressure supply device supplies an oil pressure by using the mechanical oil pump and the electric oil pump in combination or by switching between the mechanical oil pump and the electric oil pump in accordance with a traveling condition of a vehicle.

SUMMARY OF INVENTION

The electric oil pump suctions oil from an oil reservoir formed in an oil pan via an oil passage. When the electric oil pump is stopped and the suction of oil is stopped, the air that has entered through gaps between components or the air that has accumulated in a strainer that filters oil enters the oil passage, so that the oil leaks from the oil passage. As a result, when the electric oil pump is operated again, the electric oil pump may suction the air in the oil passage and idle until the air is discharged, which may result in delay of the discharge of the oil.

It is required to prevent air from entering the oil passage connecting the electric oil pump and the oil reservoir and to improve the responsiveness of the electric oil pump.

According to an aspect of the present invention, an oil pressure supply device includes:

a first oil pump configured to be operated by a traveling drive source of a vehicle;

a second oil pump configured to be operated by a motor different from the traveling drive source and to be switched between an operation and a stop according to a traveling condition of the vehicle;

a pressure regulating circuit configured to regulate an oil pressure generated by the first oil pump and the second oil pump and supply the regulated oil pressure to an oil chamber;

an oil passage configured to connect the second oil pump with an oil source; and

a check valve provided in the oil passage.

According to the above aspect, it is possible to prevent air from entering the oil passage connecting the electric oil pump and the oil source, and to improve the responsiveness of the electric oil pump.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram of a belt continuously variable transmission.

FIG. 2 is a diagram schematically showing a configuration of an oil pressure supply device.

FIG. 3 is a diagram showing a specific configuration of a check valve provided in an oil passage.

FIG. 4 is an enlarged view around the check valve in FIG. 3 .

FIG. 5 is a diagram showing a specific configuration of a check valve provided in an oil passage.

FIG. 6 is a diagram showing an operation of the check valve during an operation of an electric oil pump.

FIG. 7 is a diagram showing an operation of the check valve when the electric oil pump is stopped.

FIG. 8 is a diagram showing a case where a check valve is not provided in an oil passage as a comparative example.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a belt continuously variable transmission 1.

FIG. 2 is a diagram schematically showing a configuration of an oil pressure supply device 2.

As shown in FIG. 1 , the belt continuously variable transmission 1 for a vehicle includes, as a transmission mechanism, a pair of pulleys, i.e., a primary pulley P1 and a secondary pulley P2, and an endless belt B wound around the pair of pulleys.

In the belt continuously variable transmission 1, a speed ratio of rotation transmitted between the primary pulley P1 and the secondary pulley P2 is changed by changing winding radii of the belt B at the primary pulley P1 and the secondary pulley P2.

The winding radii of the belt B at the primary pulley P1 and the secondary pulley P2 are changed by regulating oil pressures supplied to an oil chamber R1 and an oil chamber R2 attached to the primary pulley P1 and the secondary pulley P2, respectively.

The belt continuously variable transmission 1 includes the oil pressure supply device 2. The oil pressure supply device 2 regulates, by a pressure regulating circuit 70, the oil pressure generated by a mechanical oil pump 3 and an electric oil pump 4, and supplies the regulated oil pressures to the oil chambers R1 and R2.

The mechanical oil pump 3 is an oil pump that is driven by rotation received from a vehicle drive source such as an engine. The mechanical oil pump 3 is switched between an operation and a stop in conjunction with an operation and a stop of the vehicle drive source. The electric oil pump 4 is driven by rotation received from a motor installed separately from the vehicle drive source. The operation and the stop of the electric oil pump 4 are switched by switching between the operation and the stop of the motor by a control device (not shown).

The electric oil pump 4 may be operated in place of the mechanical oil pump 3 when the mechanical oil pump 3 is stopped, for example, at the time of idling stop of the vehicle. Alternatively, the electric oil pump 4 may be operated in combination with the mechanical oil pump 3 when a high oil pressure is required due to a downshift of the belt continuously variable transmission 1 or the like.

As shown in FIG. 2 , the belt continuously variable transmission 1 includes a transmission case 5 that houses a transmission mechanism, and an oil pan 6 that stores oil OL is provided at a lower portion of the transmission case 5 in a vertical line VL direction. The oil pan 6 covers a lower opening of the transmission case 5. An oil reservoir PL which is an oil source is formed in the oil pan 6, and the mechanical oil pump 3 and the electric oil pump 4 suction the oil OL from the oil reservoir PL.

Due to layout restrictions, the transmission case 5 is inclined such that a front end side of the transmission case is positioned above a rear end side of the transmission case in a front-rear direction of the vehicle. The oil pan 6 attached to the transmission case 5 is also inclined upward from a rear end side toward a front end side of the oil pan in the front-rear direction of the vehicle.

Inside the oil pan 6, a control valve body 7 is disposed in a state of being fixed to the lower portion of the transmission case 5. The pressure regulating circuit 70 (see FIG. 1 ) is built in the control valve body 7.

A strainer 8 is fixed to a lower portion of the control valve body 7. The strainer 8 includes a suction port 81 for the oil OL in a lower portion thereof, and includes a filter F for filtering the oil OL in an inner portion thereof.

The mechanical oil pump 3 and the electric oil pump 4 are installed at an upper portion of the strainer 8 in the vertical line VL direction. In FIG. 2 , in order to make the positional relation easy to understand, the mechanical oil pump 3 and the electric oil pump 4 are schematically shown in a circular shape, and suction ports 31 and 41 shown in FIG. 2 are schematically shown with only positions thereof.

The mechanical oil pump 3 and the electric oil pump 4 are connected to oil passages 21 and 22 (see FIG. 1 ) provided inside the control valve body 7, respectively, and suction the oil OL stored in the oil pan 6 via the strainer 8.

The mechanical oil pump 3 is disposed near a rear end of the strainer 8 in the front-rear direction of the vehicle, and the electric oil pump 4 is disposed near a front end of the strainer 8. The mechanical oil pump 3 and the electric oil pump 4 are respectively provided along line segments X1 and X2 parallel to each other, but since the mechanical oil pump 3 and the electric oil pump 4 are disposed at the upper portion of the strainer 8 disposed in an inclined manner, a straight line La orthogonal to the line segments X1 and X2 is inclined at a predetermined angle θ with respect to a horizontal line HL.

Due to this inclination, a lower portion of the mechanical oil pump 3 disposed near the rear end of the upper portion of the strainer 8 is positioned in the oil reservoir PL, and a lower portion of the electric oil pump 4 is positioned in air above a liquid surface of the oil reservoir PL.

As shown in FIG. 1 , the mechanical oil pump 3 and the electric oil pump 4 are provided with the suction ports 31 and 41 for the oil OL, respectively, and the strainer 8 is provided with connection ports 82 and 83. The suction ports 31 and 41 and the connection ports 82 and 83 are connected to each other via the oil passages 21 and 22, respectively.

As shown in FIG. 2 , due to the inclination of the strainer 8, the suction port 31 provided in the lower portion of the mechanical oil pump 3 is positioned in the oil reservoir PL, and the suction port 41 provided in the lower portion of the electric oil pump 4 is positioned in the air. Since FIG. 1 is a schematic diagram, the suction port 31 of the mechanical oil pump 3 is also shown above the oil reservoir PL for convenience.

As shown in FIG. 1 , the oil passage 22 connecting the suction port 41 of the electric oil pump 4 and the connection port 83 of the strainer 8 is provided with a check valve 91 as a valve device that prevents backflow of the oil OL in the oil passage 22 when the electric oil pump 4 is stopped.

The oil OL suctioned by the mechanical oil pump 3 and the oil OL suctioned by the electric oil pump 4 are supplied from discharge ports 32 and 42 to the pressure regulating circuit 70 via oil passages 23 and 24, respectively.

The oil passages 23 and 24 are provided with check valves 92 and 93, respectively. The check valve 92 is a valve device that prevents backflow of the oil OL in the oil passage 23 when the mechanical oil pump 3 is stopped. The check valve 93 is a valve device that prevents backflow of the oil OL in the oil passage 24 when the electric oil pump 4 is stopped.

The detailed configuration and operation of the check valves 91, 92, and 93 will be described later.

The pressure regulating circuit 70 includes solenoids those are formed inside the control valve body 7 (see FIG. 2 ) and those are driven by commands (energization) of the control device (not shown), and pressure regulating valves those operate based on signal pressures generated by the solenoids.

A first pressure regulating valve 71 regulates a line pressure based on the oil pressure generated by the electric oil pump 4 by regulating a drain amount of the oil OL from the first pressure regulating valve 71. The first pressure regulating valve 71 also supplies a part of the oil OL into the transmission case 5 (see FIG. 2 ) as a lubricating oil that lubricates components of the belt continuously variable transmission 1.

The line pressure regulated by the first pressure regulating valve 71 is supplied to a second pressure regulating valve 72, a primary pressure regulating valve 73, and a secondary pressure regulating valve 74.

The second pressure regulating valve 72 regulates a pilot pressure based on the line pressure.

The pilot pressure regulated by the second pressure regulating valve 72 is supplied to a solenoid 75 on a primary pulley P1 side and a solenoid 76 on a secondary pulley P2 side.

The solenoids 75 and 76 are connected to the primary pressure regulating valve 73 and the secondary pressure regulating valve 74, respectively. The solenoids 75 and 76 are controlled by the control device (not shown), regulate the supplied pilot pressures to desired signal pressures, and supply the signal pressures to the primary pressure regulating valve 73 and the secondary pressure regulating valve 74.

The primary pressure regulating valve 73 and the secondary pressure regulating valve 74 regulate, according to the signal pressures, the line pressure supplied from the first pressure regulating valve 71 to operating pressures, and supply the operating pressure to the oil chambers R1 and R2.

FIG. 3 is a diagram showing a specific configuration of the check valve 93 provided in the oil passage 24.

FIG. 4 is an enlarged view around the check valve 93 in FIG. 3 .

In the following description, a direction in which the oil OL is fed from the oil reservoir PL to the pressure regulating circuit 70 by the suction of the electric oil pump 4 is referred to as an oil feeding direction. FIG. 3 shows an upstream side end portion 24 a of the oil passage 24 in the oil feeding direction (hereinafter, simply referred to as an “upstream side end portion 24 a”), which is connected to the discharge port 42 of the electric oil pump 4.

As shown in FIG. 3 , the oil passage 24 is mainly formed inside the control valve body 7. The upstream side end portion 24 a extends from the transmission case 5 to a control valve body 7 side and is formed inside a wall portion 51 connected to the control valve body 7.

The control valve body 7 is provided with a cylindrical wall portion 77 surrounding an outer periphery of the oil passage 24, and a distal end portion 511 of the wall portion 51 is fitted to an outer periphery of a distal end of the cylindrical wall portion 77. Thus, the inner peripheral side of the cylindrical wall portion 77 communicates with the inside of the wall portion 51. The oil passage 24 is connected to the inside of the control valve body 7 from the upstream side end portion 24 a formed inside the wall portion 51.

In the wall portion 51, a circular opening portion 51 a that communicates the discharge port 42 of the electric oil pump 4 with the upstream side end portion 24 a of the oil passage 24 is formed so as to penetrate the wall portion 51 in a thickness direction. The opening portion 51 a is provided such that an opening direction (a direction of an axis X3 that passes through a center of the opening 51 a and that is orthogonal to an opening surface of the opening portion 51 a in FIG. 3 ) is orthogonal to an axis Y direction along a direction in which the oil passage 24 extends in the control valve body 7.

As shown in FIG. 4 , on an outer periphery of the opening portion 51 a, a cylindrical peripheral wall portion 54 surrounding the opening portion 51 a at a predetermined interval is provided with an inner diameter D2 larger than an opening diameter D1 of the opening portion 51 a. Inside the peripheral wall portion 54, a cylindrical spacer 55 and a seal ring 56 are provided such that an opening 55 a of the spacer 55 and an opening 56 a of the seal ring 56 are oriented along the opening direction of the opening portion 51 a.

The seal ring 56 is positioned on the electric oil pump 4 side of the spacer 55, and is sandwiched between the spacer 55 and a wall portion 43 surrounding the discharge port 42 of the electric oil pump 4.

An opening diameter D3 of the opening 55 a of the spacer 55 is smaller than the opening diameter D1 of the opening portion 51 a and larger than an opening diameter Dx of the discharge port 42 of the electric oil pump 4, and an opening diameter of the opening 56 a of the seal ring 56 is larger than the opening diameter Dx of the discharge port 42.

The discharge port 42 of the electric oil pump 4, the opening 56 a of the seal ring 56, and the opening 55 a of the spacer 55 are concentrically disposed on an extension of the opening portion 51 a (on the axis X3), and the movement of the oil OL discharged from the electric oil pump 4 into the oil passage 24 is not blocked by the spacer 55 or the seal ring 56.

The check valve 93 is installed in the oil passage 24 on the opposite side of the spacer 55 with the opening portion 51 a interposed between the spacer 55 and the oil passage 24.

The check valve 93 is a so-called flapper valve, and includes a valve body 94 that is movable forward and backward in the direction of the axis X3, and a spring Sp that biases the valve body 94 toward the opening portion 51 a side in the direction of the axis X3.

The valve body 94 is made of, for example, an aluminum alloy, and includes a disk-shaped valve portion 95 and a columnar shaft portion 96, which are integrally formed. The valve portion 95 is disposed such that one end surface 95 a side faces the opening portion 51 a side. The shaft portion 96 is provided on the other end surface 95 b side of the valve portion 95, and extends in the direction of the axis X3.

The wall portion 51 is provided with a housing portion 513 for the check valve 93 at a position facing the opening portion 51 a. The housing portion 513 is open to the inside of a connection portion of the oil passage 24 on the extension of the opening portion 51 a (on the axis X3), and houses the check valve 93 moved in a direction away from the opening portion 51 a.

The housing portion 513 is a space having an inner diameter slightly larger than an outer diameter D4 of the valve portion 95 of the valve body 94, and a support portion 53 for the valve body 94 is formed at a center of a bottom portion 513 a of the housing portion 513 so as to protrude toward the oil passage 24 (the electric oil pump 4).

In the support portion 53, a hole portion 530 into which the shaft portion 96 of the check valve 93 is inserted is provided so as to be open on the oil passage 24 side, and the hole portion 530 extends linearly along the axis X3 in the support portion 53 in a direction away from the oil passage 24.

One end of the hole portion 530 on the opening portion 51 a side in the direction of the axis X3 is an opening end 530 a. A bottom portion 530 b is formed at the other end of the hole portion 530, and the hole portion 530 is closed.

The hole portion 530 extends to the inside of the wall portion 51 beyond the inner diameter side of the support portion 53. The shaft portion 96 of the check valve 93 is inserted into the hole portion 530 from the opening end 530 a.

As shown in FIG. 4 , a portion of the support portion 53 surrounding the opening end 530 a of the hole portion 530 is a valve seat portion 531. When a distal end 96 b of the shaft portion 96 moves to the bottom portion 530 b and the entire length of the shaft portion 96 is housed in the hole portion 530, a step portion 951 formed at a center of the valve portion 95 abuts against the valve seat portion 531 surrounding the opening end 530 a of the hole portion 530.

The spring Sp is externally inserted and attached to an outer periphery of the support portion 53. One end of the spring Sp is positioned in the direction of the axis X3 on an inner peripheral surface of the oil passage 24, and the other end of the spring Sp abuts against the other end surface 95 b of the valve portion 95.

In the present embodiment, the spring Sp is compressed in the direction of the axis X3 in a state in which the valve portion 95 of the check valve 93 abuts against the end surface 55 b of the spacer 55.

Therefore, when the electric oil pump 4 is stopped, the valve portion 95 is pressed against the end surface 55 b of the spacer 55 by a biasing force of the spring Sp, and is held at a position where the opening portion 51 a is closed.

When the electric oil pump 4 is operated in this state, a pressing force of the oil OL discharged from the electric oil pump 4 acts on the valve portion 95. Therefore, when the pressing force becomes larger than the biasing force of the spring Sp, the valve portion 95 is pushed back in a direction away from the spacer 55 while compressing the spring Sp in the direction of the axis X3 (see FIG. 4 ).

Thus, the valve portion 95 is pushed into the oil passage 24 to a position where the step portion 951 on the other end surface 95 b side abuts against the valve seat portion 531, and the opening portion 51 a closed by the valve portion 95 is open.

Thus, the discharge port 42 of the electric oil pump 4 communicates with the oil passage 24 in the wall portion 51, and thus the oil OL discharged from the electric oil pump 4 is supplied into the oil passage 24 of the control valve body 7 through the upstream side end portion 24 a.

In this way, the check valve 93 provided in the oil passage 24 switches between communication and block between the oil passage 24 and the discharge port 42 of the electric oil pump 4 in accordance with the operation and the stop of the electric oil pump 4.

The check valve 92 shown in FIG. 1 , which is provided in the oil passage 23 connecting the mechanical oil pump 3 and the pressure regulating circuit 70 may also be a flapper valve having the same configuration as the check valve 93. Although detailed description is omitted, the check valve 92 switches between communication and block between the oil passage 23 and the discharge port 32 of the mechanical oil pump 3 in accordance with the operation and the stop of the mechanical oil pump 3.

FIG. 5 is a diagram showing a specific configuration of the check valve 91 provided in the oil passage 22.

As shown in FIG. 5 , the check valve 91 is provided at an upstream side end portion 22 a of the oil passage 22 in the oil feeding direction (hereinafter, simply referred to as an “upstream side end portion 22 a”), which is connected to the connection port 83 of the strainer 8.

The upstream side end portion 22 a is provided with an opening portion 22 b communicating with the connection port 83. The opening portion 22 b is formed in a separate plate 78 disposed inside the control valve body 7. The connection port 83 protruding upward from the strainer 8 is fitted into the control valve body 7 and faces the opening portion 22 b provided inside the control valve body 7.

An opening direction of the opening portion 22 b is disposed along an axis X direction which is an opening direction of the connection port 83, and the opening portion 22 b is positioned above the connection port 83 in the vertical line VL direction (see FIG. 2 ). By the suction of the electric oil pump 4, the oil OL flows from below upwards in the gravity direction and flows through the connection port 83 and the opening portion 22 b, and is introduced into the oil passage 22.

The check valve 91 is a flapper valve having the same configuration as the check valve 93, and includes a valve body 94 including the valve portion 95 and the shaft portion 96. The shaft portion 96 is slidably supported in a hole portion 22 c formed inside the control valve body 7 in which the oil passage 22 is formed. The hole portion 22 c is provided along the axis X direction which is the opening direction of the opening portion 22 b, and a support portion 22 d is formed on an outer periphery of the hole portion 22 c. The spring Sp for biasing the valve portion 95 is externally inserted into the support portion 22 d.

While the electric oil pump 4 is stopped, the valve portion 95 is pressed against the opening portion 22 b by the biasing force of the spring Sp to close the opening portion 22 b. When the electric oil pump 4 is operated, a negative pressure generated by the electric oil pump 4 suctioning the oil OL is applied. When the negative pressure becomes larger than the biasing force of the spring Sp, the valve portion 95 of the check valve 91 is displaced in a direction away from the opening portion 22 b, and the opening portion 22 b is open.

In this way, the check valve 91 opens and closes the opening portion 22 b in accordance with the operation and the stop of the electric oil pump 4, thereby switching between communication and block between the oil passage 22 and the connection port 83 of the strainer 8.

Here, as shown in FIG. 1 , the check valve 92 provided on the discharge port 32 side of the mechanical oil pump 3 and the check valve 93 provided on the discharge port 42 side of the electric oil pump 4 are required to have pressure resistance because a high oil pressure, which is an original pressure of the line pressure, is applied to the check valves 92 and 93. As described above, the check valves 92 and 93 may be valve bodies 94 made of, for example, an aluminum alloy in order to improve the pressure resistance.

On the other hand, the pressure applied to the check valve 91 provided on the suction port 41 side of the electric oil pump 4 during the operation of the electric oil pump 4 is a negative pressure lower than the original pressure. Therefore, since the required pressure resistance is lower than that of the check valves 92 and 93, for example, the valve body 94 of the check valve 91 may be made of a resin.

Hereinafter, the operation of the check valves 91 and 93 during the operation and the stop of the electric oil pump 4 in the oil pressure supply device 2 according to the present embodiment will be described.

FIG. 6 is a diagram showing the operation of the check valves 91 and 93 during the operation of the electric oil pump 4.

Here, a case where the electric oil pump 4 is operated in combination with the mechanical oil pump 3 will be described. In FIGS. 6 to 8 , the configuration around the check valve 93 is shown in a simplified manner.

For example, when a high oil pressure is required due to the downshift or the like of the belt continuously variable transmission 1, the electric oil pump 4 is operated to increase the oil pressure supplied by the mechanical oil pump 3.

When the electric oil pump 4 is operated by the control device (not shown) and suction of the oil OL is started, as shown in FIG. 6 , the check valve 91 of the oil passage 22 receives a negative pressure and is displaced in a direction in which the opening portion 22 b is open, whereby the oil passage 22 communicates with the connection port 83 of the strainer 8. Thus, the oil OL in the oil reservoir PL filtered by the strainer 8 flows through the oil passage 22 and is suctioned into the electric oil pump 4.

When the electric oil pump 4 discharges the suctioned oil OL from the discharge port 42, the check valve 93 of the oil passage 24 receives the oil pressure which is the original pressure of the line pressure, and is displaced in a direction in which the opening portion 51 a is open. Thus, the oil passage 24 communicates with the discharge port 42 of the electric oil pump 4. The oil OL suctioned into the electric oil pump 4 from the strainer 8 flows through the oil passage 24. The original pressure of the line pressure generated by the suction of the electric oil pump 4 is supplied to the pressure regulating circuit 70 via the oil passage 24.

The original pressure supplied by the electric oil pump 4 is regulated together with an original pressure supplied by the mechanical oil pump 3 in the pressure regulating circuit 70, and is supplied to the oil chambers R1 and R2.

FIG. 7 is a diagram showing the operation of the check valves 91 and 93 when the electric oil pump 4 is stopped.

When a required amount of oil pressure is supplied to the oil chambers R1 and R2, the control device (not shown) stops the electric oil pump 4.

When the electric oil pump 4 is stopped, as shown in FIG. 7 , the oil pressure is not applied to the check valve 93 of the oil passage 24, so that the check valve 93 is displaced, by the biasing force of the spring Sp, in a direction in which the opening portion 51 a is closed, and blocks the communication between the oil passage 24 and the discharge port 42 of the electric oil pump 4.

Similarly, since the negative pressure of the electric oil pump 4 is not applied to the check valve 91 of the oil passage 22, the check valve 91 is displaced, by the biasing force of the spring Sp, in a direction in which the opening portion 22 b is closed, and blocks the communication between the oil passage 22 and the connection port 83 of the strainer 8.

In this way, in the present embodiment, when the electric oil pump 4 is stopped, an upstream side and a downstream side of the electric oil pump 4 are blocked by the check valves 91 and 93, respectively.

Hereinafter, the operation in the case where either or both of the check valves 91 and 93 are not provided will be described as comparative examples 1, 2, and 3. In order to distinguish from the present embodiment, in the comparative examples 1, 2, and 3, the oil passages 22 and 24 are replaced with oil passages 22A and 24A (see FIG. 8 ).

Comparative Example 1: Case where Both of Check Valves 91 and 93 are not Provided

When the electric oil pump 4 is stopped, the oil OL flows back to the electric oil pump 4 side from the mechanical oil pump 3 or the pressure regulating circuit 70 via the oil passage 24A. This backflow reduces the amount of the oil OL supplied from the mechanical oil pump 3 to the pressure regulating circuit 70. Thus, it is necessary to increase a discharge amount of the mechanical oil pump 3, which affects fuel consumption in the vehicle.

Comparative Example 2: Case where Check Valve 91 is not Provided

FIG. 8 is a diagram showing the comparative example 2.

Unlike the comparative example 1, since the check valve 93 is provided in the oil passage 24A, it is possible to prevent the backflow from the mechanical oil pump 3 to the electric oil pump 4. On the other hand, when the suction of the oil OL by the electric oil pump 4 is stopped in the oil passage 22A, air enters the oil passage 22A from gaps between components such as the suction port 41 of the electric oil pump 4 positioned in the air. The air accumulated in the strainer 8 may enter the inside of the oil passage 22A.

In this way, when air enters the oil passage 22A in which the check valve 91 is not provided, the oil OL leaks from the oil passage 22A.

When the electric oil pump 4 is operated in a state in which the oil OL is leaked from the oil passage 22A, the electric oil pump 4 may suction the air that first enters the oil passage 22A and may idle, and the timing at which the discharge of the oil OL is started may be delayed.

Comparative Example 3: Case where Check Valve 93 is not Provided

By providing the check valve 91 in the oil passage 22A, it is possible to prevent the oil from leaking from the oil passage 22A. However, as described above, the oil OL flows back from the mechanical oil pump 3 or the pressure regulating circuit 70 to the electric oil pump 4 side via the oil passage 24A in which the check valve 93 is not provided. The check valve 91 is normally operated by the negative pressure generated by the suction of the electric oil pump 4, and is not required to have pressure resistance. However, when a high pressure is applied to the valve body 94 due to the backflow of the oil OL, the product life of the check valve 91 may be shortened.

As described above, in the case where the electric oil pump 4 is used in combination with the mechanical oil pump 3 at the time of a downshift or the like in which a high oil pressure is required, it is required to quickly supply the oil pressure to the oil chambers R1 and R2.

Therefore, as shown in FIG. 7 , in the present embodiment, by providing the check valve 91 in the oil passage 22, it is possible to reduce the amount of air entering the oil passage 22 through gaps between components such as the suction port 41 when the electric oil pump 4 is stopped. Thus, the oil OL is prevented from leaking from the oil passage 22.

As shown in FIG. 6 , when the electric oil pump 4 is operated in a state in which the oil OL is present in the oil passage 22, the idling due to the suction of air is reduced. Further, since the electric oil pump 4 suctions the oil OL in the oil passage 22 and starts to discharge the oil OL before the check valve 91 of the oil passage 22 is open, the electric oil pump 4 promptly supplies the oil pressure to the oil chambers R1 and R2.

Further, as shown in FIG. 2 , the electric oil pump 4 suctions the oil OL stored in the oil reservoir PL. The oil OL is oil which is stirred in the oil reservoir PL by the rotation of the components of the belt continuously variable transmission 1 and then falls into the oil pan 6 along a wall surface of the transmission case 5 or the like. Therefore, the oil OL in the oil reservoir PL contains a large amount of air particles K. The oil OL containing the air particles K is suctioned into the strainer 8. The air particles K move upward in the vertical line VL direction inside the strainer 8 due to buoyancy, and form an air reservoir Air.

As described above, in the strainer 8, the front end side where the electric oil pump 4 is disposed is positioned above the rear end side where the mechanical oil pump 3 is disposed in the vertical line VL direction. Therefore, the air reservoir Air is easily formed on the front end side of the strainer 8 where the electric oil pump 4 is disposed.

As described in the comparative example 3, in the case where the check valve 91 is not provided in the oil passage 22, when the electric oil pump 4 is stopped, the air in the air reservoir Air formed on the front end side of the strainer 8 may enter the oil passage 22 through the connection port 83 (see FIG. 1 ) due to the suction of the oil OL by the mechanical oil pump 3. Accordingly, a large amount of air may be suctioned when the electric oil pump 4 is operated, and the discharge timing may be delayed.

In the present embodiment, when the electric oil pump 4 is stopped, the check valve 91 blocks the communication between the oil passage 22 and the connection port 83 of the strainer 8, whereby when the electric oil pump 4 is stopped, the air accumulated on the front end side of the strainer 8 can be prevented from entering the oil passage 22 through the connection port 83 and the oil OL can be prevented from leaking from the oil passage 22.

When the electric oil pump 4 is operated, since the electric oil pump 4 suctions the oil OL inside the oil passage 22 and starts to discharge the oil OL, it is unlikely to lead to a discharge delay of the electric oil pump 4 even when the air in the air reservoir Air is suctioned after the check valve 91 is retracted to cause the oil passage 22 and the connection port 83 to communicate with each other.

Further, in the present embodiment, by providing the check valve 93 in the oil passage 24 as well, when the electric oil pump 4 is stopped, it is possible to prevent the oil OL from flowing back to the electric oil pump 4 side from the mechanical oil pump 3 or the pressure regulating circuit 70. This prevents a reduction in the amount of the oil OL supplied from the mechanical oil pump 3 to the pressure regulating circuit 70, and further prevents a high pressure from being applied to the check valve 91 of the oil passage 22 by the backflow of the oil OL.

As described above,

(1) The oil pressure supply device 2 according to the present embodiment includes:

-   -   the mechanical oil pump 3 (first oil pump) configured to be         operated by a traveling drive source of the vehicle;     -   the electric oil pump 4 (second oil pump) configured to be         operated by a motor different from the traveling drive source         and to be switched between an operation and a stop according to         a traveling condition of the vehicle;     -   the pressure regulating circuit 70 configured to regulate an oil         pressure generated by the mechanical oil pump 3 and the electric         oil pump 4 and supply the regulated oil pressure to the oil         chambers R1 and R2;     -   the oil passage 22 configured to connect the electric oil pump 4         with the oil reservoir PL (oil source); and     -   the check valve 91 provided in the oil passage 22.

When the electric oil pump 4 is stopped, air may enter the oil passage 22 through gaps or the like between components, and the air may cause the oil OL to leak from the oil passage 22 connecting the oil reservoir PL and the electric oil pump 4. When the oil OL leaks from the oil passage 22, if the electric oil pump 4 is operated again, the electric oil pump 4 idles until the air is discharged, and the discharge of the oil OL may be delayed.

When the electric oil pump 4 is used during the stop of the mechanical oil pump 3, such as idling stop, a slight operation delay does not cause a problem. On the other hand, in the case where the electric oil pump 4 is used as an auxiliary for the mechanical oil pump 3 when a high oil pressure is required, for example, when a continuously variable transmission is downshifted, the electric oil pump 4 is required to operate promptly.

In the present embodiment, by providing the check valve 91 in the oil passage 22, it is possible to prevent the oil OL from leaking from the oil passage 22 due to entry of air when the electric oil pump 4 is stopped, and it is possible to improve the operational responsiveness of the electric oil pump 4.

(2) The check valve 91 is provided in a portion of the oil passage 22 through which the oil OL suctioned by the electric oil pump 4 flows from below upwards in the gravity direction.

The check valve 91 is provided at the upstream side end portion 22 a of the oil passage 22 that is connected to the connection port 83 of the strainer 8, and opens and closes the opening portion 22 b. During the operation of the electric oil pump 4, the oil OL flows from below upwards in the gravity direction in the opening portion 22 b. Therefore, when the electric oil pump 4 is stopped, the oil OL flows backward to the downstream side due to gravity, and the oil OL is likely to leak from the oil passage 22. Thus, by providing the check valve 91 that opens and closes the opening portion 22 b, it is possible to prevent backflow and appropriately prevent oil leakage from the oil passage 22.

(3) The electric oil pump 4 is disposed in air, and the check valve 91 is disposed in the oil reservoir PL which is an oil source.

When a direction of the oil passage 22 from the oil reservoir PL toward the electric oil pump 4 is defined as an oil feeding direction, a downstream side of the check valve 91 in the oil feeding direction is closed by the check valve 91. Therefore, the oil OL does not leak, and even when the electric oil pump 4 is disposed in the air, the suction of air is prevented. Since the check valve 91 itself is disposed in the oil, it is possible to prevent air from being suctioned in an upstream side of the check valve 91 in the oil feeding direction.

(4) The strainer 8 configured to filter the oil OL is disposed in the oil reservoir PL,

-   -   the mechanical oil pump 3 and the electric oil pump 4 suction         the oil OL from the oil reservoir PL via the strainer 8,     -   the strainer 8 includes         -   the connection port 82 (first connection port) for supplying             the oil OL to the mechanical oil pump 3, and         -   the connection port 83 (second connection port) provided             above the connection port 82 in the gravity direction and             connected to the oil passage 22, and     -   the check valve 91 blocks communication between the oil passage         22 and the connection port 83 when the electric oil pump 4 is         stopped.

The mechanical oil pump 3 and the electric oil pump 4 suction the oil OL from the common strainer 8, and the connection port 83 connected to the electric oil pump 4 is positioned above the connection port 82 connected to the mechanical oil pump 3.

The oil OL stored in the oil reservoir PL may contain air by being stirred by a rotating body of a vehicle. When the oil OL containing air is suctioned into the strainer 8, the air moves upward in the gravity direction, and the air reservoir Air is easily formed in the vicinity of the connection port 83.

The check valve 91 blocks the communication with the connection port 83 when the electric oil pump 4 is stopped, thereby preventing the air in the air reservoir Air from entering the oil passage 22 from the connection port 83. Thus, when the electric oil pump 4 is operated again, it is possible to reduce a discharge delay due to the suction of air into the oil passage 22.

(5) The check valve 91 is

-   -   a flapper valve provided with a valve body 94 that is movable         forward and backward in an opening direction (axis X direction)         of the opening portion 22 b of the oil passage 22 communicating         with the connection port 83, and that opens and closes the         opening portion 22 b.

By using a flapper valve as the check valve 91, it is possible to increase a flow rate of the oil OL when the oil passage 22 is open as compared with, for example, a ball valve.

The above description of the embodiments of the invention is merely one example of application of the invention, and is not intended to limit the technical scope of the invention to the specific configuration of the above embodiments.

While the embodiments of the present invention have been described above, the above description of the embodiments of the invention is merely one example of application of the invention, and is not intended to limit the technical scope of the invention to the specific configuration of the above embodiments.

In the present embodiment, as shown in FIG. 2 , an example in which the transmission case 5 is disposed to be inclined due to layout restrictions or the like has been described, but the present invention is not limited thereto. For example, if the layout is relatively free, the transmission case 5, the oil pan 6, and the strainer 8 may be horizontally disposed without being inclined, and the suction port 41 of the electric oil pump 4 may be positioned in the oil in the oil reservoir PL.

The present application claims a priority of Japanese Patent Application No. 2019-238014 filed with the Japan Patent Office on Dec. 27, 2019, all the contents of which are hereby incorporated by reference. 

1-5. (canceled)
 6. An oil pressure supply device comprising: a check valve; a strainer; a first oil pump configured to be operated by a traveling drive source of a vehicle; and a second oil pump configured to be operated by a motor, wherein a first connection port of the strainer is connected to the first oil pump; a second connection port of the strainer is connected to the second oil pump via the check valve; and the second connection port is positioned at a higher position in a gravity direction than the first connection port.
 7. An oil pressure supply device comprising: a check valve; a strainer; a first oil pump configured to be operated by a traveling drive source of a vehicle; and a second oil pump configured to be operated by a motor, wherein a first connection port of the strainer is connected to the first oil pump; a second connection port of the strainer is connected to the second oil pump via the check valve; and an upper portion of the strainer is configured to be inclined upward in a gravity direction from the first connection port toward the second connection port.
 8. The oil pressure supply device according to claim 6, wherein the check valve is provided in a portion through which oil suctioned by the second oil pump flows from below upwards in the gravity direction.
 9. The oil pressure supply device according to claim 6, wherein the second oil pump is disposed in air; and the check valve is disposed in an oil reservoir which is an oil source.
 10. The oil pressure supply device according to claim 6, wherein the check valve includes: a plate shaped valve body; and a spring which biases the plate shaped valve body toward the second connection port of the strainer.
 11. The oil pressure supply device according to claim 6, wherein an oil pressure is supplied to a continuously variable transmission from the first oil pump and/or the second oil pump; and both of the first oil pump and the second oil pump are operated when the continuously variable transmission is downshifted.
 12. The oil pressure supply device according to claim 7, wherein the check valve is provided in a portion through which oil suctioned by the second oil pump flows from below upwards in the gravity direction.
 13. The oil pressure supply device according to claim 7, wherein the second oil pump is disposed in air; and the check valve is disposed in an oil reservoir which is an oil source.
 14. The oil pressure supply device according to claim 7, wherein the check valve includes: a plate shaped valve body; and a spring which biases the plate shaped valve body toward the second connection port of the strainer.
 15. The oil pressure supply device according to claim 7, wherein an oil pressure is supplied to a continuously variable transmission from the first oil pump and/or the second oil pump; and both of the first oil pump and the second oil pump are operated when the continuously variable transmission is downshifted. 